Precursor delivery system

ABSTRACT

A precursor source vessel comprises a vessel body, a passage within the vessel body, and a valve attached to a surface of the body. An internal chamber is adapted to contain a chemical reactant, and the passage extends from outside the body to the chamber. The valve regulates flow through the passage. The vessel has inlet and outlet valves, and optionally a vent valve for venting internal gas. An external gas panel can include at least one valve fluidly interposed between the outlet valve and a substrate reaction chamber. Gas panel valves can each be positioned along a plane that is generally parallel to, and no more than about 10.0 cm from, a flat surface of the vessel. Filters in a vessel lid or wall filter gas flow through the vessel&#39;s valves. A quick-connection assembly allows fast and easy connection of the vessel to a gas panel.

CLAIM FOR PRIORITY

The present application claims priority under 35 U.S.C. 119(e) to U.S.Provisional Patent Application No. 60/850,886, filed Oct. 10, 2006.

BACKGROUND

1. Field

The present application relates generally to semiconductor processingequipment and specifically to apparatus for delivering reactant gases toprocessing chambers.

2. Description of the Related Art

Chemical vapor deposition (CVD) is a known process in the semiconductorindustry for forming thin films of materials on substrates such assilicon wafers. In CVD, reactant gases (also referred to herein as“precursor gases”) of different reactants are delivered to one or moresubstrates in a reaction chamber. In many cases, the reaction chamberincludes only a single substrate supported on a substrate holder (suchas a susceptor), with the substrate and substrate holder beingmaintained at a desired process temperature. The reactant gases reactwith one another to form thin films on the substrate, with the growthrate being controlled either by the temperature or the amounts ofreactant gases.

In some applications, the reactant gases are stored in gaseous form in areactant source vessel. In such applications, the reactant vapors areoften gaseous at ambient (i.e., normal) pressures and temperatures.Examples of such gases include nitrogen, oxygen, hydrogen, and ammonia.However, in some cases, the vapors of source chemicals (“precursors”)that are liquid or solid (e.g., hafnium chloride) at ambient pressureand temperature are used. These source chemicals may have to be heatedto produce sufficient amounts of vapor for the reaction process. Forsome solid substances (referred to herein as “solid source precursors”),the vapor pressure at room temperature is so low that they have to beheated to produce a sufficient amount of reactant vapor and/ormaintained at very low pressures. Once vaporized, it is important thatthe vapor phase reactant is kept at or above the vaporizing temperaturethrough the processing system so as to prevent undesirable condensationin the valves, filters, conduits, and other components associated withdelivering the vapor phase reactants to the reaction chamber. Vaporphase reactants from such naturally solid or liquid substances areuseful for chemical reactions in a variety of other industries.

Atomic layer deposition (ALD) is another known process for forming thinfilms on substrates. In many applications, ALD uses a solid and/orliquid source chemical as described above. ALD is a type of vapordeposition wherein a film is built up through self-saturating reactionsperformed in cycles. The thickness of the film is determined by thenumber of cycles performed. In an ALD process, gaseous precursors aresupplied, alternatingly and repeatedly, to the substrate or wafer toform a thin film of material on the wafer. One reactant adsorbs in aself-limiting process on the wafer. A different, subsequently pulsedreactant reacts with the adsorbed material to form a single molecularlayer of the desired material. Decomposition may occur through reactionwith an appropriately selected reagent, such as in a ligand exchange ora gettering reaction. In a typical ALD reaction, no more than amolecular monolayer forms per cycle. Thicker films are produced throughrepeated growth cycles until the target thickness is achieved.

A typical solid or liquid source precursor delivery system includes asolid or liquid source precursor vessel and a heating means (e.g.,radiant heat lamps, resistive heaters, etc.). The vessel includes thesolid (e.g., in powder form) or liquid source precursor. The heatingmeans heats up the vessel to increase the vapor pressure of precursorgas in the vessel. The vessel has an inlet and an outlet for the flow ofan inert carrier gas (e.g., N₂) through the vessel. The carrier gassweeps precursor vapor along with it through the vessel outlet andultimately to a substrate reaction chamber. The vessel typicallyincludes isolation valves for fluidly isolating the contents of thevessel from the vessel exterior. Ordinarily, one isolation valve isprovided upstream of the vessel inlet, and another isolation valve isprovided downstream of the vessel outlet. Precursor source vessels arenormally supplied with tubes extending from the inlet and outlet,isolation valves on the tubes, and fittings on the valves, the fittingsbeing configured to connect to the gas flow lines of the remainingsubstrate processing apparatus. It is often desirable to provide anumber of additional heaters for heating the various valves and gas flowlines between the precursor source vessel and the reaction chamber, toprevent the precursor gas from condensing and depositing on suchcomponents. Accordingly, the gas-conveying components between the sourcevessel and the reaction chamber are sometimes referred to as a “hotzone” in which the temperature is maintained above thevaporization/condensation temperature of the precursor.

It is known to provide a serpentine or tortuous flow path for the flowof carrier gas while it is exposed to a solid or liquid precursorsource. For example, U.S. Pat. Nos. 4,883,362; 7,122,085; and 7,156,380each disclose such a serpentine path.

SUMMARY

In one aspect, a chemical reactant source vessel comprises a vesselbody, a passage within the vessel body, and a valve attached directly toa surface of the vessel body. The vessel body defines an internalchamber adapted to contain a solid or liquid chemical reactant, and thepassage extends from outside the vessel body to the chamber. The valveis configured to regulate flow through the passage.

In another aspect, a gas delivery system for a vapor phase reactor forvapor processing of substrates comprises a vapor phase reaction chamberfor processing substrates, a vessel adapted to contain a solid or liquidchemical reactant, an inlet valve connected to a generally flat surfaceof the vessel, an outlet valve connected to the generally flat surfaceof the vessel, a gas flow path through the vessel from the inlet valveto the outlet valve, and a plurality of gas panel valves. The gas flowpath is configured to convey a gas so as to contact a solid or liquidchemical reactant contained within the vessel. The gas panel valvesinclude at least one valve downstream of the outlet valve and fluidlyinterposed between the outlet valve and the reaction chamber. The gaspanel valves are each positioned along a plane that is generallyparallel to the flat surface of the vessel, the plane being no more thanabout 10.0 cm from the flat surface of the vessel.

In another aspect, a chemical reactant source vessel comprises acontainer, a valve, and a filter. The container defines an internalchamber adapted to contain a solid or liquid chemical reactant. A wallof the container has a passage extending to the chamber from outside thecontainer. The valve is attached to the wall and is adapted to regulategas flow to and from the chamber through the passage. The filter is inthe wall and is adapted to prevent particulate matter from flowingthrough the passage.

In yet another aspect, a gas delivery system for a vapor phase reactorfor vapor processing of substrates comprises a vapor phase reactionchamber for processing substrates, a vessel adapted to contain a solidor liquid chemical reactant, an outlet valve connected to the vessel, agas delivery system for delivering reactant gas flow from the outletvalve to the reaction chamber, a vapor exhaust component downstream ofthe reaction chamber, a vent valve connected to the vessel, and one ormore conduits for delivering gas flow from the vent valve to the exhaustcomponent without flowing through the gas delivery system or thereaction chamber.

In still another aspect, an apparatus for connecting a chemical reactantsource vessel to a gas interface assembly of a vapor phase reactor forvapor processing of substrates is provided. The apparatus comprises avessel, a gas interface assembly of a vapor phase reactor, and aconnection assembly for connecting the vessel to the gas interfaceassembly. The vessel has a chamber adapted to contain a solid or liquidchemical reactant. The vessel includes an inlet and an outlet in fluidcommunication with the chamber. The gas interface assembly has a gasinlet adapted to connect to the outlet of the vessel chamber. Theconnection assembly comprises a track component and a lift assembly. Thetrack component includes one or more elongated tracks adapted to movablyengage one or more track engagement members of the vessel. The liftassembly is configured to move the track component vertically between alowered position and a raised position. When the vessel's one or moretrack engagement members engage the one or more tracks of the trackcomponent, and when the lift assembly moves the track component to itsraised position, the vessel's outlet becomes positioned to substantiallydirectly fluidly communicate with the gas inlet of the gas interfaceassembly.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught herein without necessarilyachieving other objects or advantages as may be taught or suggestedherein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments of the presentinvention will become readily apparent to those skilled in the art fromthe following detailed description of the preferred embodiments havingreference to the attached figures, the invention not being limited toany particular preferred embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention will be readily apparent to theskilled artisan in view of the description below, the appended claims,and from the drawings, which are intended to illustrate and not to limitthe invention, and wherein:

FIG. 1 is a schematic illustration of a conventional precursor sourceassembly and a reactor chamber assembly.

FIG. 2 is a perspective view of a conventional solid precursor sourcevessel.

FIG. 3 is an illustration of both ideal and less than ideal sourcechemical concentrations in reactant gas pulses for atomic layerdeposition.

FIG. 4 is a schematic illustration of a conventional precursor sourcevessel and gas panel.

FIG. 5 is a schematic illustration of a precursor source vessel withsurface-mounted valves and a gas panel.

FIG. 6 is a schematic illustration of a precursor source vessel withsurface-mounted valves and a gas panel in close thermal contact with thevessel.

FIG. 7 is a perspective view of a preferred embodiment of a precursorsource vessel, a gas interface assembly for fluidly communicating withthe vessel, and a quick-connection assembly for connecting anddisconnecting the vessel to the gas interface assembly.

FIG. 8 is an exploded perspective view of the vessel of FIG. 7.

FIG. 9 is a rear perspective sectional view of the vessel of FIG. 7.

FIG. 10 is a rear sectional view of the vessel of FIG. 7.

FIG. 11 is a top perspective view of an alternative embodiment of avessel body.

FIG. 12 is an exploded perspective view of an embodiment of a serpentineinsert comprising a stack of trays.

FIG. 13 is a perspective view of an upper stacking tray of theserpentine insert of FIG. 12.

FIG. 14 is a top view of the upper stacking tray of FIG. 13.

FIG. 15 is a perspective view of a lower stacking tray of the serpentineinsert of FIG. 12.

FIG. 16 is a top view of the lower stacking tray of FIG. 15.

FIG. 17 is a sectional view of a filter mounted on a lid of a precursorsource vessel.

FIG. 18 is an embodiment of a filter material that can be used for thefilter of FIG. 17.

FIG. 19 is a schematic illustration of a gas delivery system for flowingcarrier and reactant gases through a precursor source vessel and a vaporphase reaction chamber.

FIGS. 20 and 21 are front perspective views of the vessel and gasinterface assembly of FIG. 7, shown connected.

FIG. 22 is a top front perspective view of the precursor source vesseland gas interface assembly of FIG. 7, with an alternative embodiment ofa quick-connection assembly.

FIG. 23 is a top front perspective view of the vessel and gas interfaceassembly of FIG. 22, shown connected.

FIG. 24 is a bottom front perspective view of the vessel and gasinterface assembly of FIG. 22, shown separated.

FIG. 25 is a schematic illustration of the gas delivery system of FIG.19, with a vent valve and dedicated vent line added to the precursorsource vessel.

FIG. 26 is a perspective view of a precursor source vessel with a ventvalve.

FIG. 27 is a perspective view of the vessel of FIG. 26 connected to thegas interface assembly of FIGS. 22-24.

FIG. 28 is a sectional view of the vessel of FIG. 26, with the additionof a dedicated heating device for the vessel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present application for letters patent discloses improved precursorsource vessels, apparatuses and methods for loading and connecting thevessels to a reactor, and interfaces for using the vessels with vaporprocessing reactors. The disclosed embodiments provide excellent accessto reactant vapor, reduced contamination of the reactor's gas deliverysystem, and improved serviceability (e.g., replacement or recharging) ofthe precursor source vessel.

The following detailed description of the preferred embodiments andmethods details certain specific embodiments to assist in understandingthe claims. However, one may practice the present invention in amultitude of different embodiments and methods, as defined and coveredby the claims.

Gas Delivery System Overview

FIG. 1 schematically illustrates a conventional precursor deliverysystem 6 for feeding a gas phase reactant generated from a solid orliquid precursor source vessel 10 into a gas phase reaction chamber 12.Skilled artisans will understand that the precursor delivery systems ofthe present invention may incorporate many of the aspects of the gasdelivery system 6 of FIG. 1. Accordingly, the conventional deliverysystem 6 is now described in order to better understand the invention.

With reference to FIG. 1, the solid or liquid source vessel 10 containsa solid or liquid source precursor (not shown). A solid source precursoris a source chemical that is solid under standard conditions (i.e., roomtemperature and atmospheric pressure). Similarly, a liquid sourceprecursor is a source chemical that is liquid under standard conditions.The precursor is vaporized within the source vessel 10, which may bemaintained at or above a vaporizing temperature. The vaporized reactantis then fed into the reaction chamber 12. The reactant source vessel 10and the reaction chamber 12 can be located in a reactant source cabinet16 and a reaction chamber vessel 18, respectively, which are preferablyindividually evacuated and/or thermally controlled. This can be achievedby providing these components with separate cooling and heating devices,insulation, and/or isolation valves and associated piping, as known inthe art.

The illustrated gas delivery system 6 is particularly suited fordelivering vapor phase reactants to be used in a vapor phase reactionchamber. The vapor phase reactants can be used for deposition (e.g.,CVD) or Atomic Layer Deposition (ALD).

As seen in FIG. 1, the reactant source vessel 10 and the reactionchamber 12 are adapted to be in selective fluid communication with eachother through a first conduit 20 so as to feed the gas phase reactantfrom the reactant source vessel 10 to the reaction chamber 12 (such asan ALD reaction chamber). The first conduit 20 includes one or moreisolation valves 22 a, 22 b, which may be used for separating the gasspaces of the reactant source vessel 10 and the reaction chamber 12during evacuation and/or maintenance of either or both of the reactantsource vessel 10 and the reaction chamber vessel 18.

Inactive or inert gas is preferably used as a carrier gas for thevaporized precursor. The inert gas (e.g., nitrogen or argon) may be fedinto the precursor source vessel 10 through a second conduit 24. Thereactant source vessel 10 includes at least one inlet for connection tothe second conduit 24 and at least one outlet for withdrawing gas fromthe vessel 10. The outlet of the vessel 10 is connected to the firstconduit 20. The vessel 10 can be operated at a pressure in excess of thepressure of the reaction chamber 12. Accordingly, the second conduit 24includes at least one isolation valve 26, which can be used for fluidlyisolating the interior of the vessel 10 during maintenance orreplacement of the vessel. A control valve 27 is preferably positionedin the second conduit 24 outside of the reactant source cabinet 16.

In another variation (which can be employed in embodiments of thepresent invention), the precursor vapor can be drawn to the reactionchamber 12 by applying a vacuum to the reactant source vessel 10,without using a carrier gas. This is sometimes referred to as “vapordraw.”

In yet another variation (which can also be employed in embodiments ofthe present invention), the precursor vapor can be drawn out of thevessel 10 by an external gas flow that creates a lower pressure outsideof the vessel, as in a Venturi effect. For example, the precursor vaporcan be drawn by flowing a carrier gas toward the reaction chamber 12along a path downstream of the vessel 10. Under some conditions, thiscan create a pressure differential between the vessel 10 and the flowpath of the carrier gas. This pressure differential causes the precursorvapor to flow toward the reaction chamber 12.

In order to remove dispersed solid particles when a solid sourceprecursor is used, the gas delivery system 6 includes a purifier 28through which the vaporized reactant is conducted. The purifier 28 maycomprise one or more of a wide variety of purifying devices, such asmechanical filters, ceramic molecular sieves, and electrostatic filterscapable of separating dispersed solids or particles or molecules of aminimum molecular size from the reactant gas flow. It is also known toprovide an additional purifier in the vessel 10. In particular, U.S.Published Patent Application No. US 2005/0000428A1 discloses a vesselcomprising a glass crucible enclosed within a steel container, thecrucible containing the reactant source and having a lid with a filter.The lid is separate from a vessel lid that attaches to the steelcontainer.

With continued reference to FIG. 1, the reactant source vessel 10 ispositioned within the reactant source cabinet 16. The interior space 30of the cabinet 16 can be kept at a reduced pressure (e.g., 1 mTorr to 10Torr, and often about 500 mTorr) to promote radiant heating of thecomponents within the cabinet 16 and to thermally isolate suchcomponents from each other to facilitate uniform temperature fields. Inother variations, the cabinet is not evacuated and includesconvection-enhancing devices (e.g., fans, cross-flows, etc.). Theillustrated cabinet 16 includes one or more heating devices 32, such asradiation heaters. Also, reflector sheets 34 can be provided, which maybe configured to surround the components within the cabinet 16 toreflect the radiant heat generated by the heating devices 32 to thecomponents positioned within the cabinet 16. Reflector sheets 34 can beprovided on the inner walls 40 of the cabinet 16, as well as on thecabinet's ceiling 7 and floor 9. In the illustrated apparatus, asubstantial length of the first conduit 20 is contained within thereactant source cabinet 16. Thus the first conduit 20 will inherentlyreceive some heat to prevent condensation of reactant vapors.

The reactant source cabinet 16 can include a cooling jacket 36 formedbetween an outer wall 38 and an inner wall 40 of the cabinet. Thecooling jacket 36 can contain water or another coolant. The jacket 36allows the outer surface 38 of the cabinet 16 to be maintained at ornear ambient temperatures.

In order to prevent or reduce gas flow from the reactant source vessel10 between the alternating pulses of an ALD process, it is possible toform an inactive gas barrier in the first conduit 20. This is alsosometimes referred to as “inert gas valving” or a “diffusion barrier” ina portion of the first conduit 20 to prevent flow of reactant from thereactant source vessel 10 to the reaction chamber 12 by forming a gasphase barrier by flowing gas in the opposite direction to the normalreactant flow in the first conduit 20. The gas barrier can be formed byfeeding inactive gas into the first conduit 20 via a third conduit 50connected to the conduit 20 at a connection point 52. The third conduit50 can be connected to an inert gas source 54 that supplies the secondconduit 24. During the time intervals between the feeding of vapor-phasepulses from the reactant source vessel 10, inactive gas is preferablyfed into the first conduit 20 through the third conduit 50. This gas canbe withdrawn via a fourth conduit 58, which is connected to the firstconduit 20 at a second connection point 60 located upstream of the firstconnection point 52 (i.e., closer to the reactant source vessel 10). Inthis manner, an inert gas flow of an opposite direction to the normalreactant gas flow is achieved (between reactant pulses) in the firstconduit 20 between the first and second connection points 52, 60. Thefourth conduit 58 can be in communication with an evacuation source 64(such as a vacuum pump). A restriction 61 and valves 56, 63, and 70 canalso be provided. Further details of the gas delivery system 6 areillustrated and described in U.S. Published Patent Application No. US2005/0000428A1.

Existing solid or liquid precursor source delivery systems, such as thesystem 6 shown in FIG. 1, have a number of drawbacks and limitations.One drawback is that it is sometimes necessary to provide a large numberof additional heaters to heat up the gas lines and valves between theprecursor source vessel (such as the vessel 10) and the reaction chamber(such as the reaction chamber 12). In particular, it is normallydesirable to maintain all of these intervening gas-conveying components(e.g., the valves 22 a, 22 b, 70, purifier 28, conduit 20) at atemperature above the condensation temperature of the precursor, toprevent the precursor vapor from depositing on such components.Typically, these intervening components are heated separately by lineheaters, cartridge heaters, heat lamps, and the like. Some systems(e.g., U.S. Published Patent Application No. 2005/0000428A1) utilizethese additional heaters to bias the intervening components to atemperature above that of the source vessel. Such temperature biasinghelps to prevent precursor condensation in the intervening componentsduring cool-down. Since the source vessel typically has a higher thermalmass than the intervening gas-conveying components, these components areat risk of cooling down to the condensation temperature faster than thesource vessel. This can lead to an undesirable condition in which thesource vessel is still producing precursor vapor that can flow to thecooler intervening components and deposit thereon. The temperaturebiasing can overcome this problem. However, the need for additionalheaters increases the total size and operating cost of the apparatus.

Further, conventional solid source delivery systems typically employfilters (such as the purifier 28 of FIG. 1) between the source vesseloutlet and the substrate reaction chamber, in order to prevent solidprecursor particles (e.g., powder entrained in the carrier gas flow)from entering the reaction chamber. Such filters also add to the totalsize of the apparatus and can require additional heaters to preventcondensation therein. Also, such filters are typically downstream of thesource vessel outlet, which involves a risk that precursor particles maydeposit on gas-conveying components downstream of the vessel outlet,such as within gas conduits or within the vessel outlet valve itself.These particles can damage components such as valves, which cancompromise their ability to completely seal.

Another drawback of conventional solid or liquid source delivery systemsis that it is often difficult to recharge or replace the precursorsource vessel. FIG. 2 shows a typical precursor source vessel 31comprising a container body 33 and a lid 35. The lid 35 includes inlettubes 43 a, 43 b and outlet tubes 45 a, 45 b extending upward therefrom.An isolation valve 37 is interposed between the inlet tubes 43 a, 43 b,and an isolation valve 39 is interposed between the outlet tubes 45 a,45 b. Another isolation valve 41 is interposed between gas linesconnecting the tubes 43 a and 45 a. The inlet tubes 43 a, 43 b andoutlet tubes 45 a, 45 b provide for the flow of an inert carrier gasthrough the container body 33. The tubes 43 a, 45 a typically includefittings 47 configured to connect to other gas flow lines of thereactant gas delivery system. When the solid or liquid source precursoris depleted and in need of replacement, it is customary to replace theentire source vessel 31 with a new one that has a full load of thesource chemical. Replacing the source vessel 31 requires shutting offthe isolation valves 37 and 39, disconnecting the fittings 47 from theremaining substrate processing apparatus, physically removing the vessel31, placing a new vessel 31 in the appropriate location, and connectingthe fittings 47 of the new vessel 31 to the remaining substrateprocessing apparatus. Often, this process also involves disassemblingvarious thermocouples, line heaters, clamps, and the like. Theseprocesses can be somewhat laborious.

Another drawback of conventional solid or liquid source delivery systemsis that the gas delivery system can produce areas of stagnant flow (alsoreferred to as “dead legs”). Dead legs tend to occur when the gas flowpath from the precursor source vessel is longer and more complex.Conventional inlet and outlet isolation valves for the source vessel (asdescribed above) can produce dead legs. In general, dead legs increasethe risk of unwanted precursor deposition on the gas-conveyingcomponents of the delivery system. Such unwanted precursor depositioncan occur due to cold spots associated with the dead volumes, whereinthe precursor solidifies at temperatures below the sublimation/meltingtemperature. Such unwanted precursor deposition can also occur due tohot spots associated with the dead volumes, wherein the precursordecomposes at high temperatures. For this reason, it is generallydesirable to reduce and minimize stagnation of the reactant gas flow. Itis also generally desirable to reduce the surface area to betemperature-controlled, in order to lessen the chance of producing hotor cold spots.

Another reason to minimize the amount and volume of dead legs is toreduce the total volume of the gas delivery system interposed betweenthe precursor source vessel and the substrate reaction chamber. As thetotal volume of the gas delivery system increases, often times theminimum pulse time and minimum purge time associated with ALD processingincrease as well. The minimum pulse time is the pulse time necessary foran injected reactant to saturate the surface of a substrate beingprocessed. The minimum purge time is the time necessary to purge excessreactant from the substrate reaction chamber and gas delivery systembetween reactant pulses. Substrate throughput (the rate at whichsubstrates can be processed) is increased when the minimum pulse timeand minimum purge time are decreased. Accordingly, it is desirable toreduce the amount and volume of dead legs in order to increasethroughput.

Another benefit of reducing the total volume of the gas delivery systemis to improve the “pulse shape” of the reactant gas pulses. The pulseshape refers to the shape of a curve of the reactant's chemicalconcentration in the reactant/carrier mixture, for a reactant gas pulse.FIG. 3 shows an example of an ideal reactant concentration curve 80, aswell as a curve 82 that is less than ideal. Both curves include reactantgas pulses 84 separated by time periods 86 of substantially zeroreactant concentration. The ideal curve 80 resembles a rectilinear wave,such as a square wave. A substantially rectilinear wave is preferredbecause it is highly desirable for each reactant gas pulse to deliverthe reactant species to all of the available reaction sites on thesubstrate surface (saturation) in the least amount of time, in order tooptimize substrate throughput. A rectilinear pulse shape, as in thecurve 80, optimizes throughput because the duration of each pulse has ahigh concentration of the reactant, which in turn reduces the pulseduration necessary to deliver sufficient reactant species to thesubstrate surface. Also, the reduced dispersion of a rectilinear pulseshape reduces the amount of “pulse overlap” between successive pulses ofdifferent precursors, which reduces the potential for unwanted CVDgrowth modes. In contrast, the pulse concentration of each pulse 84 ofthe non-ideal curve 82 takes longer to reach its maximum level, whichincreases the pulse duration necessary to fully saturate the substratesurface. Thus, the frequency of the curve 80 is less than that of thecurve 82. As the total volume of the gas delivery system increases, thepulse shape deteriorates. Accordingly, it is desirable to improve thepulse shape (i.e., make it more like a square wave) by minimizing deadlegs.

Another drawback of conventional solid source delivery systems is therisk of contamination involved in venting the precursor source vesselprior to processing. Precursor source vessels are typically suppliedwith a head pressure of gas in the vessel. For example, a source vesselfilled with precursor powder is often shipped with helium or other inertgas at a pressure slightly higher (e.g., 5 psi) than ambient pressure.Helium is typically used to enable an “out-bound” helium leak test usinga helium leak detector to ensure vessel integrity just prior toshipment. This helium is often left or replaced with N₂ or other inertgas so that if a small leak is present, the gas leaks outward from thevessel, preventing atmospheric contamination of the precursor within thevessel. Before the vessel is used in substrate processing, the headpressure of internal gas is ordinarily removed. Typically, the vessel'sinternal gas is vented out through the vessel's outlet isolation valve,through the reactant gas delivery system, and ultimately through thereactor's exhaust/scrubber. In some systems, the vessel's internal gasis vented out through the substrate reaction chamber. Other systemsemploy a gas line in parallel with the reaction chamber (i.e., extendingfrom a point just upstream of the reaction chamber to a point justdownstream of the reaction chamber), such that the vessel's internal gascan be directed to the exhaust/scrubber without flowing through thereaction chamber. In either case, current vessel designs involve a riskof particle generation when the vessel is relieved of the head pressure.This can result in precursor powder becoming entrained within the ventflow (i.e., the venting out of the internal pressurized gas of thevessel), which can contaminate and possibly damage downstream componentsof the gas delivery system, including the vessel outlet itself. Evenduring normal processing, precursor material (e.g., powder) can becomeentrained within the carrier gas flowing through the precursor sourcevessel, which involves a risk of unwanted deposition of the precursorwithin the gas delivery system.

The presently disclosed embodiments of precursor delivery systemssubstantially overcome these problems by employing an improved precursorsource vessel and apparatus for quickly connecting and disconnecting thevessel from the rest of the delivery system. These aspects are nowdescribed.

Gas Panel in Close Thermal Contact with Source Vessel

FIGS. 4-6 illustrate three different gas panel arrangements. A gas paneltypically includes one or more valves that are downstream of a precursorsource vessel, and can also include one or more valves upstream of thevessel. FIG. 4 illustrates a conventional arrangement in which a sourcechemical is contained within a source vessel 10. A gas panel 90 includesa plurality of valves operable to deliver carrier gas from a carrier gassource (not shown) through the vessel 10 and into a reaction chamber(not shown). An inlet valve 91 is connected upstream of the vessel 10 bytubing 93, and an outlet valve 92 is connected downstream of the vessel10 by tubing 94. In this conventional arrangement, the inlet valve 91,the outlet valve 92, and the valves and tubing of the gas panel 90 aretypically not in close thermal contact with the vessel 10.

FIG. 5 illustrates an arrangement that is somewhat improved relative tothat of FIG. 4. In the arrangement of FIG. 5, a precursor source vessel100 has a surface-mounted inlet valve 108 and a surface-mounted outletvalve 110. The valves 108 and 110 are separated from a conventional gaspanel 90 by tubing 95 and 96. In this arrangement, the valves 108 and110 are in close thermal contact with the vessel 100, but the valves andtubing of the gas panel 90 are not.

FIG. 6 illustrates an arrangement that is improved relative to that ofFIG. 5. In the arrangement of FIG. 6, the source vessel 100 has agenerally flat upper surface with a surface-mounted inlet valve 108 anda surface-mounted outlet valve 110. Also, a gas panel 97 is arrangedsuch that the valves and tubing of the gas panel are positioned along aplane that is generally parallel to the generally flat surface of thevessel 100. In order to increase thermal contact between the vessel 100and the gas panel valves and tubing, the distance between the plane ofthe gas panel valves and tubing and the generally flat surface of thevessel 100 is preferably no more than about 10.0 cm, more preferably nomore than about 7.5 cm, and even more preferably no more than about 5.3cm.

Source Vessel with Surface Mounted Valves and Serpentine Path

FIG. 7 shows a preferred embodiment of an improved solid or liquidprecursor source vessel 100 and a quick-connection assembly 102. Thesource vessel 100 includes a container body 104 and a lid 106. The lid106 includes surface-mounted isolation valves 108 and 110, described inmore detail below.

FIGS. 8-10 show the source vessel 100 of FIG. 7 in greater detail. FIG.8 is an exploded view, and FIGS. 9 and 10 are rear cross-sectionalviews, of the source vessel 100. The illustrated vessel 100 includes thecontainer body 104, a serpentine path insert 112 within the body 104,and the lid component 106. The illustrated assembly is fastened togetherby fastening elements 124, such as screws or nut and bolt combinations.The fastening elements 124 are adapted to extend into aligned holeswithin a flange 126 of the body 104. Skilled artisans will appreciatethat the assembly can be fastened together by a variety of alternativemethods.

The serpentine path insert 112 preferably defines a tortuous orserpentine path 111 through which a carrier gas must travel as it flowsthrough the vessel 100. The serpentine path 112 preferably contains theprecursor source, such as a powder or liquid. Causing the carrier gas toflow through a long serpentine path 111 while exposed to the precursorsource causes the carrier gas to carry more reactant vapor. Theserpentine path 111 is significantly longer than the carrier gas flowpathway within conventional precursor source vessels. Since the carriergas is required to flow along a longer path while exposed to theprecursor source, it is exposed to the precursor source for a longertime and is thus more likely to become saturated with the precursor. Theserpentine path 111 also reduces the importance of heating up the vessel100 during processing, because the carrier gas becomes exposed to morereactant chemical for a longer residence time, the practical effectbeing a reduction in the required temperature forsublimation/vaporization. The valves 108 and 110 (described below) andthe valve 210 (described below with reference to FIGS. 25-28) aresubjected to a less severe environment, thereby increasing theirreliability. The reduced temperature requirement also increases thecomponent options in the design. Performance is also improved because itis easier to deliver sufficient amounts of reactant vapor to thereaction chamber. Also, during ALD processing, the concentration of eachreactant pulse becomes less time-variant. In other words, as the carriergas approaches full saturation with the reactant vapor, the reactantpulse shape becomes closer to a rectilinear wave.

A spring 114 is preferably provided to bias the serpentine insert 112against the lid 106, to prevent the escape of reactant gas through theinterface between the insert 112 and the lid 106. In other words, thespring 114 tends to reduce the risk of the gas bypassing some or all ofthe serpentine path. Suitable springs 114 include flat wire compressionsprings, such as the Spirawave® wave springs sold by Smalley Steel RingCompany of Lake Zurich, Ill.

In an alternative embodiment, the serpentine path 111 is machineddirectly into the container body 104 or vessel lid 106. For example,FIG. 11 shows a container body 104 having an integrally formedserpentine path 111 machined directly therein.

In another alternative embodiment, illustrated in FIGS. 12-16, theserpentine insert 112 comprises a plurality of stacked trays thatcollectively define a serpentine gas flow path. For example, FIG. 12shows a plurality of stacked trays 230, 240 that are configured to beremovably inserted into a container body 104 (FIGS. 7-10) and thatcollectively define a spiral gas flow path that comprises at least aportion of the tortuous path of the vessel 100. In FIGS. 12-16, theheights of the trays 230, 240 are enhanced for ease of illustration. Itshould be understood that the trays can be made vertically thinner sothat the vessel 100 has a diameter significantly greater than itsoverall height.

In the illustrated embodiment, four trays are stacked: three upper trays230 and one lower tray 240. The number of trays can vary based onparameters such as the sublimation rate, carrier flow, etc.

Referring to FIGS. 13 and 14, each upper tray 230 includes a soliddivider 231, preventing gas flow therethrough and extending the fullheight of the tray 230, and a partial divider 232 that allows gas flowtherethrough. Preferably, the partial divider includes a screen 233configured to retain large precursor particulates while allowing freegas flow therethrough. In the illustrated embodiment, the screen 233extends across the top portion of the partial divider 232, while a solidpanel completes the height of the partial divider 232. An annular rim234 also extends the height of the upper tray 230. The solid divider 231and the partial divider 232 together define a main compartment 235 forholding solid source material (not shown) and an outer channelcompartment 236 that is open at the lower surface of the tray 230. Theillustrated upper tray 230 has a central core 237 that includes acentral channel 238 to accommodate a gas inlet pipe that deliverscarrier gas to the bottom tray 240. The illustrated upper tray 230 alsohas a plurality of pegs 239 on an upper surface thereof and acorresponding plurality of holes (not shown) on a bottom surface thereoffor receiving the pegs of another tray therebelow. As will be betterunderstood in view of the operation, described hereinbelow, the holes onthe lower surface of the central core 237 are desirably rotationallyoffset relative to the pegs 239 on the upper surface, serving toproperly align the plurality of trays upon one another to define thewinding flow path. In certain preferred embodiments, the corners in themain compartment to which the flow is exposed are rounded to minimizeflow stagnation from sharply angled corners.

Referring to FIGS. 15 and 16, the lowest tray 240 comprises a soliddivider 241, preventing gas flow therethrough and extending the fullheight of the tray 240, and a partial divider 242 that allows gas flowthereover. Preferably, the partial divider 242 simply provides anopening to the central channel 238 in the middle of the overlying uppertray 230, as will be better understood in view of the description ofFIG. 12. An annular rim 244 also extends the height of the lower tray240. The rim 244, the solid divider 241 and the partial divider 242together define a main compartment 245 for holding solid source material(not shown) and an outer channel compartment 246. In preferredembodiments, the solid source material only fills the main compartment245 up to and even with channel compartment 246. In alternateembodiments, the solid source material fills the between one third andtwo thirds of the height of the main compartment. The illustrated lowertray 240 also has a central core 247 into which the channel compartment246 protrudes, a plurality of pegs 249 on an upper surface thereof and acorresponding plurality of holes (not shown) on a bottom surface thereoffor receiving pegs that protrude upwardly from a floor of the containerbody 104 (FIGS. 7-10).

The stack of trays 230, 240 is assembled as shown in the exploded viewof FIG. 12. The main compartments 235, 245 for each of the upper trays230 and the lower tray 240 are loaded with a precursor source chemical,preferably in the form of powder. The lower tray 240 and plurality ofupper trays 230 are stacked upon one another and loaded into theexternal container body 104. The trays 230, 240 are aligned by the pegs239, 249 and corresponding holes such that gas flows into each tray,preferably at least flowing a lap of within 200°-355° around the maincompartment and then up into the channel compartment 236 of theoverlying upper tray 230. The container lid 106 (FIGS. 7 and 8) is thenclosed and sealed over the container body 104, and a central pipe 215extending from the lid extends down through the central channels 238 ofthe upper trays 230 to open into the channel compartment 246 of thelower tray 240. FIG. 12 shows the central pipe 215 but not the lid 106.The central pipe 215 is configured to deliver carrier gas conveyed intoan inlet of the vessel 100. In certain preferred embodiments, a springor other biasing device (not shown) is often placed below 240 to biasall the trays together, preventing leaks from the central core to adifferent level.

In operation, inert gas is preferably delivered to the stack of trays230, 240, and experiences a long and winding flow route horizontally,preferably through an arc of about 200°-350° of the main compartment ineach tray 230, 240 before vertically exiting that tray. In theillustrated embodiment, inert carrier gas is provided through a centralinlet 215 that extends down through the aligned central channels 238 ofthe upper trays 230 to open into the channel compartment 246 of thelower tray 240. The inert gas winds through the precursor sourcechemical in the main compartment 245 until encountering an opening inthe lower surface of the overlying upper tray 230. This opening allowsthe carrier gas, and the vaporized precursor it carries with it, to passinto the channel compartment 236 of the overlying upper tray 230, fromwhich the gas passes through the screen 233 (FIG. 13) and into the maincompartment 235. The gas winds through solid precursor in that maincompartment 235, preferably through an arc of about 200°-350° beforeencountering an opening in the lower surface of the overlying upper tray230, etc. At the uppermost upper tray 230, the gas is allowed to exitthe vessel 100, preferably through a surface-mounted outlet valve 110(described below) at the lid vessel 106. It will be understood, ofcourse, that the flow path can be reversed if desired. In other words,the inert carrier gas can begin in a top tray and flow downward throughthe stack of trays.

Referring again to FIGS. 8-10, in the illustrated embodiment the vessellid 106 includes an inlet valve 108 and an outlet valve 110. The inletvalve 108 has an inlet end that receives carrier gas via a conduit 121.The conduit 121 has a fitting 122 adapted for connection to a fitting131 (FIG. 7) of a gas line 133 of a gas interface assembly 180(described below). The inlet valve 108 also has an outlet end that ispreferably in fluid communication with a first portion 117 (such as anend portion) of the serpentine path 111 of the insert 112. The outletvalve 110 has an inlet end that is preferably in fluid communicationwith a second portion 119 (such as an end portion) of the serpentinepath 111, and an outlet end in fluid communication with a suitable gasoutlet of the lid 106, such as an orifice 128. In use, carrier gas flowsinto the conduit 121 and through the inlet valve 108, serpentine path111, and outlet valve 110 before exiting from the orifice 128. Thus,results that may be achieved by this embodiment include mounting theisolation valves onto the surface of the lid 106, and causing thecarrier gas to flow along a tortuous or serpentine path while it isexposed to the precursor source. Skilled artisans will appreciate thatthe vessel 100 can be configured differently.

As explained above, conventional solid or liquid precursor sourcevessels include discrete tubes that extend from the vessel body or lid,with the valves being attached inline with such tubes. For example, theconventional vessel 31 of FIG. 2 includes discrete tubes 43 b and 45 bextending upward from the lid 35, with the valves 37 and 39 beingattached to such tubes. The valves 37 and 39 of the vessel 37 are notdirectly attached to or in contact with the lid 35. As a result, thereactant gas from the vessel 31 flows out of the outlet tube 45 b andthen into the outlet valve 39, which may involve a flow path withstagnant or dead gas volumes. In addition, the isolation valves 37, 39,and 41 of the conventional vessel 31 are significantly thermallyisolated from the vessel lid 35 and body 33. Both the tubing and thevalves are very difficult to effectively heat with three-dimensionalgeometry, regardless of the presence or absence of dead volumes or “deadlegs.” The valves have a smaller thermal mass than the lid 35 and body33 and therefore tend to heat up and cool down faster. That is why, inconventional systems, additional heaters (such as line heaters,cartridge heaters, directed heat lamps, etc.) are often usedspecifically to provide heat to the valves and associated tubing duringsystem cool-down, to prevent such components from cooling down fasterthan the vessel 31 (which can create an unwanted condition in whichreactant vapors flow into such components and deposit thereon). Anotherproblem with the conventional valves and tubing is that they can heat upfaster than the vessel 31. For some precursors, this can create acondition in which the valves and tubing become warmer than thedecomposition temperature of the precursor, causing the precursor todecompose and deposit thereon.

In contrast, the isolation valves 108 and 110 (FIGS. 7-10) of the sourcevessel 100 are preferably mounted directly to the surface of the lid 106of the vessel 100. Such surface mount technology may be referred to asan integrated gas system. In comparison to conventional precursor sourcevessels (e.g., FIG. 2), the surface-mounted valves 108 and 110 canreduce the volume of dead legs (stagnant reactant gas flow) in the gasdelivery system by eliminating tubing between the valves and the vessel100, which simplifies and shortens the travel path of the reactant gas.The valves and tubing are much more amenable to heating due to thecompressed geometry and improved thermal contact, which lessenstemperature gradients. The illustrated surface-mounted valves 108 and110 have valve porting blocks 118 and 120, respectively, whichpreferably include valve seats and adjustable flow restrictors (e.g.,diaphragms) for selectively controlling gas flow through the valveseats. Such valves 108 and 110 isolate the vessel 100 by restricting allgas flow through the valve seats. The porting blocks 118, 120 can beformed integrally with the vessel lid 106 or can be separately formedand mounted thereon. In either case, the porting blocks 118, 120preferably have a relatively high degree of thermal contact with thevessel lid 106. This causes the temperatures of the valves 108 and 110to remain close to that of the lid 106 and container body 104 duringtemperature changes of the vessel 100. This surface-mounted valveconfiguration can reduce the total number of heaters required to preventcondensation of vaporized precursor gas. When the vessel 100 is abovethe vaporization temperature of the precursor source chemical, vaporizedprecursor can freely flow to the valves 108 and 110. Since the valves108, 110 closely track the temperature of the vessel 100 duringtemperature ramping, the valves are also likely to be above thevaporization temperature, thus reducing the need for additional heatersto prevent condensation of the precursor in the valves. The shortenedgas flow paths are also better suited for controlled heating. Thesurface-mounted valves 108 and 110 also have a much smaller packagingspace requirement.

Each of the valves 108 and 110 preferably comprises a valve portingblock including gas flow passages that can be restricted or opened bythe valve. For example, with reference to FIGS. 9 and 10, the portingblock 118 of valve 108 preferably includes an internal gas flow passageextending from the conduit 121 through one side 123 of the porting block118 to a region 113. The region 113 preferably includes an internalapparatus (not shown) for restricting the flow of the gas, such as avalve seat and a movable restrictor or diaphragm. In one embodiment, themovable internal restrictor or diaphragm can be moved by turning a knob(e.g., the larger cylindrical upper portion 181 of the valve 108) eithermanually or in an automated fashion. Another internal gas flow passagepreferably extends from the region 113 through an opposite side 125 ofthe block 118 to an inlet passage that extends through the lid 106 intothe vessel 100. For example, the inlet passage can extend into thetortuous path 111 defined by the serpentine insert 112. The valve 110and vent valve 210 (described below with reference to FIGS. 25-28) canbe configured similarly to valve 108. In one embodiment, the valves 108and 110 are pneumatic valves. It is particularly preferred to form thevalve porting blocks 118 and 120 integrally with the vessel lid 106.This eliminates the need for separate seals therebetween.

In another embodiment, the valves 108, 110, and 210 (FIGS. 25-28) areformed without porting blocks, such as porting blocks 118, 120, and arepreferably formed integrally with a portion of the vessel 100, such asthe vessel lid 106.

Filter

Preferably, the precursor source vessel includes a filtration apparatusfor filtering the gas flow through the vessel, to prevent particulatematter (e.g., the source chemical's powder) from escaping the vessel.The filtration apparatus can be provided in a lid of the vessel,preferably underneath a surface-mounted valve 108, 110, and/or 210(FIGS. 25-28). Preferably, the filtration apparatus comprises a separatefilter for each inlet and outlet of the vessel.

FIG. 17 is a sectional view of one embodiment of a filtration apparatus130, which can be installed in the body or lid (e.g., lid 106 of FIG. 8)of a reactant source vessel. The illustrated apparatus 130 is a filterformed of a flange 132, a filter media 134, and a fastener element 136.In this embodiment, the filter 130 is sized and shaped to fit closelyinto a recess 138 of the vessel's lid (e.g., lid 106 of FIG. 8). Theperimeter of the flange 132 can be circular, rectangular, or othershapes, and the shape preferably conforms tightly to the perimeter ofthe recess 138. The filter material 134 is configured to restrict thepassage of gas-entrained particles greater than a certain size throughan opening defined by an annular inner wall 140 of the flange 132. Thematerial 134 preferably blocks the entire opening defined by the wall140. The material 134 can comprise any of a variety of differentmaterials, and in one embodiment is a high flow sintered nickel fibermedia. In other embodiments, the filter media is manufactured from othermetals (e.g., stainless steel), ceramics (e.g., alumina), quartz, orother materials typically incorporated in gas or liquid filters. Thematerial 134 is preferably welded or adhered to the annular wall 140. Inone embodiment, the filter 130 comprises a surface-mount sandwichfilter, such as those sold by TEM Products of Santa Clara, Calif.

In the illustrated embodiment, the fastener element 136 comprises aspring snap ring that biases the flange 132 against a wall 146 of thelid 106. The ring 136 preferably fits closely within an annular recess142 in the perimeter of the recess 138. The snap ring 136 can comprise,for example, a flat wire compression spring, such as the Spirawave® wavesprings sold by Smalley Steel Ring Company of Lake Zurich, Ill.Additional and different types of fastener elements can be provided tofasten the filter 130 to the lid 106. Preferably, the fastener element136 prevents the flow of carrier gas and reactant vapor through theinterface between the flange 132 and the lid 106, such that all of thegas must flow through the filter material 134. A sub-recess 147 can beprovided to define a plenum 148 on an outlet side of the filter 130,which can improve the quality of the filtered gas flow. The illustratedfilter 130 is easily replaceable, simply by removing the snap ring 136from the annular recess 142, removing the filter 130 from the recess138, inserting a new filter 130, and reinserting the snap ring 136 intothe annular recess 142.

The filter recess 138 is preferably located closely to one of theisolation valves of the precursor source vessel. In the embodiment ofFIG. 17, the recess 138 is directly below the valve porting block 120 ofthe outlet isolation valve 110 (FIG. 1) of the source vessel 100.Skilled artisans will understand that individual filters 130 may beprovided in association with each isolation valve of the vessel,including the inlet valve 108 and the vent valve 210 (FIGS. 25-28). Apassage 145 extends from the plenum 148 to a passage 144 of the valveporting block 120. In the illustrated embodiment, the porting block 120is formed separately from the vessel lid 106, and a seal is preferablyprovided therebetween. In another embodiment, the block 120 is formedintegrally with the lid 106 and the passages 144 and 145 are formed inthe same drilling operation.

FIG. 18 is a magnified sectional view a surface portion of a filtermaterial 134 in accordance with one embodiment. In this embodiment, thefilter material 134 includes a large particle filtration layer 150 and asmall particle filtration layer 152. The large particle filtration layer150 preferably filters relatively larger particles, and the smallparticle filtration layer 152 preferably filters relatively smallerparticles. The large particle filtration layer 150 includes a pluralityof voids 151. In one embodiment, the large particle filtration layer 150is about 20-60% void, and more preferably 30-50% void. In oneembodiment, the large particle filtration layer 150 is about 42% void.The large particle filtration layer 150 can comprise, for example, astainless steel material. The large particle filtration layer 150preferably comprises a majority of the filter material 134. Due to thevoids 151, the filter material 134 produces a relatively low pressuredrop. One or more support tubes 154 can be provided for enhancedstructural rigidity of the large particle filtration layer 150. Thesmall particle filtration layer 152 can have a pore size of 0.05-0.2microns, and more preferably about 0.10 microns. The small particlefiltration layer 152 can have a thickness of about 5-20 microns, andmore preferably about 10 microns. The small particle filtration layer152 may comprise, for example, a coating of Zirconia. Each side of thelarge particle filtration layer 150 can be coated with a small particlefiltration layer 152. A suitable filter material is one that is similarto an AccuSep filter sold by Pall Corporation.

Gas Interface Assembly

FIG. 19 is a schematic illustration of a gas delivery system 160 thatcan be used to flow carrier and reactant gases through the precursorsource vessel 100 and a vapor phase reaction chamber 162. The deliverysystem 160 includes the vessel 100, a carrier gas source 164, adownstream purifier or filter 166, and several additional valves, asdescribed herein. The isolation valves 108, 110 are preferablysurface-mounted on the vessel 100 as described above. The carrier gassource 164 is operable to deliver an inert carrier gas to a connectionpoint 168. A valve 170 is interposed between the connection point 168and the vessel inlet valve 108. A valve 172 is interposed between theconnection point 168 and a connection point 174. A valve 176 isinterposed between the connection point 174 and the vessel outlet valve110. The purifier 166 and an additional valve 178 are interposed betweenthe connection point 174 and the reaction chamber 162. As illustrated,the vessel 100 can have appropriate control and alarm interfaces,displays, panels, or the like.

When it is desirable to flow the carrier gas through the vessel 100 andto the reaction chamber 162, the valves 170, 108, 110, 176, and 178 areopened and the valve 172 is closed. Conversely, when it is desirable forthe carrier gas to bypass the vessel 100 on its way to the reactionchamber 162, the valves 172 and 178 are opened, and preferably all ofthe valves 170, 108, 110, and 176 are closed. The valve 178 can be usedto isolate the reaction chamber 162 from the gas delivery system 160,e.g. for maintenance and repair.

With reference again to FIG. 7, a precursor gas delivery system (such asthat shown in FIG. 19) can be embodied in a gas interface assembly 180that facilitates control of the flow of carrier gas and reactant vaporthrough the vessel 100 and an associated vapor phase reaction chamber.The illustrated gas interface assembly 180 includes a plurality ofvalves 182 (which can perform substantially the same functions as thevalves 170, 172, 176, and 178 of FIG. 19), a downstream purifier orfilter 184, and a heater plate 186. The valves 182 can include valveporting blocks 188 similar in principle and operation to the valveporting blocks 118 and 120.

With reference to FIGS. 7 and 19, a gas line 133 extends from one of thevalves 182 that receives carrier gas from a carrier gas source 164. Forexample, the valve 182 from which the gas line 133 extends can performsubstantially the function of valve 170 of FIG. 19. FIG. 7 does not showthe gas line extending into such a valve from the carrier gas source,but it will be understood to be provided. The gas line 133 includes afitting 131 that connects to the carrier gas inlet fitting 122 of thevessel 100 when the vessel and the gas interface assembly 180 areconnected. An outlet 135 of the gas interface assembly 180 delivers gasto a reaction chamber 162. It will be understood that the sourcevessel's carrier gas inlet could be configured to be similar to theoutlet orifice 128.

With continued reference to FIG. 7, the heater plate 186 heats up thevalves 182 and the vessel 100, preferably to a temperature above thevaporization temperature of the precursor. The high level of thermalcontact between the various valves, valve porting blocks, and gasconduits of the preferred embodiment, as well as the proximity of theheater plate 186 to these components, reduces the total heat required toprevent condensation of the precursor in the gas-conveying componentsdownstream of the vessel 100. The heater plate 186 can be heated by avariety of different types of heaters, such as cartridge heaters or lineheaters. The heater plate can be formed of a variety of materials, suchas aluminum, stainless steel, titanium, or various nickel alloys.Thermofoil-type heaters can also be used to heat the heater plate 186and valve porting blocks 188. The use of a thermofoil-type heater canallow variable watt density or more than one temperature control zone.Incorporation of variable watt density or multiple temperature controlzones on the heater plate 186 can make it possible to induce atemperature gradient along the flow path of the gas. This can provide agradual heating of the reactant vapor as it moves downstream, so thatcondensation is avoided. Suitable thermofoil heaters are sold by Mincoof Minneapolis, Minn. Additional heaters (including line heaters,cartridge heaters, radiant heat lamps, and thermofoil-type heaters) canalso be provided to heat the vessel lid 106 and container body 104.

In certain embodiments, a dedicated heater can be provided to heat thevessel 100. In one particular embodiment, shown in FIG. 18 (described infurther detail below), a dedicated heating device 220 is providedbeneath a lower surface of the vessel's container body 104.

As mentioned above, precursor vapor can also be drawn from the vessel100 by the “vapor draw” and external gas flow methods. In the vapor drawmethod, a vacuum is applied to the vessel 100 to draw out the vapor. Forexample, the vacuum can be applied downstream of the reaction chamber162, with the valves 110, 176, and 178 open and the valves 108, 170, and172 closed. The vacuum can be applied, for example, by using a vacuumpump. In the external gas flow method, the precursor vapor can be drawnfrom the vessel 100 by flowing the carrier gas from the source 164 tothe reaction chamber 162, with the valves 110, 172, 176, and 178 openand the valves 108 and 170 closed. Under certain conditions, this cancreate a pressure differential between the vessel 100 and the flow pathof the carrier gas, which causes the precursor vapor to flow toward thereaction chamber.

Quick-Connection Assembly

With continued reference to FIG. 7, the quick-connection assembly 102preferably facilitates quicker and easier loading, aligning, andconnection of the precursor source vessel 100 to the gas interfaceassembly 180. The quick-connection assembly 102 is ergonomicallyfriendly and facilitates replacement, recharging, and serviceability ofthe vessel 100. A variety of different types of quick-connectionassemblies can be provided, keeping in mind these goals, and skilledartisans will understand that the illustrated assembly 102 is merely oneembodiment. The quick-connection assembly 102 can be incorporated intothe vacuum enclosure where the source vessel 100 and supporting controlhardware are packaged.

With reference to FIGS. 7, 20, and 21, the illustrated quick-connectionassembly 102 includes a base 190, a pedestal 192 extending upward froman edge of the base 190, a track component 194, and a lift assembly 196.The base 190 can preferably be secured to a lower inner surface of thegas delivery system 6 (FIG. 1), such as on the floor 9 of the reactantsource cabinet 16. Preferably, the pedestal 192 is connected to andsupports the gas interface assembly 180 at a position above the base190. The track component 194 includes a platform 198 and two rollertracks 200 on opposite sides of the platform 198. A pair of rollerassemblies 202 having aligned rollers 204 is preferably secured toopposite sides of the vessel 100. In this embodiment, the rollers 204are sized and configured to roll within the tracks 200 of the trackcomponent 194, so that the vessel 100 can be easily and quicklypositioned on the platform 198.

When the vessel 100 is loaded onto the platform 198 with the rollerassemblies 202 engaged with the tracks 200, the outlet of the outletvalve 110 is preferably vertically aligned with an inlet of one of thevalves 182 of the gas interface assembly 180. The lift assembly 196 isconfigured to move the platform 198 vertically between lowered (shown inFIG. 7) and raised positions (shown in FIGS. 20-21). When the vessel 100is loaded onto the platform 198 and the platform is moved to its raisedposition, the outlet of the outlet valve 110 preferably communicates,either directly or indirectly, with an inlet of one of the valves 182. Aminimal degree of manual adjustment may be required to suitably seal theinterface between the outlet of the outlet valve 110 and the inlet ofthe valve 182. In the illustrated embodiment, the outlet of the outletvalve 110 is an orifice 128 in the valve porting block 120. In thismanner, the quick-connection assembly 102 enables quick connection ofthe precursor source vessel 100 and the gas interface assembly 180.

As shown in FIG. 20, the illustrated lift assembly 196 comprises a lifthandle 195 that can manually actuate scissor legs 197 to vertically movethe platform 198. For example, the handle 195 and legs 197 can operatein a manner that is similar to some existing auto jacks. In oneembodiment, the lift assembly 196 lifts the platform 198 to its raisedposition when the handle 195 is rotated approximately 180°. However, itwill be appreciated that other types of lift devices can alternativelybe provided.

The quick-connection assembly 102 makes it easier to exchange a depletedvessel 100 with a new vessel. In addition, since the assembly 102simplifies vessel removal and installation, it is also easier to performroutine maintenance on the vessel 100. Preferably, the weight of thevessel 100 is such that it can be easily managed by a single technician.

FIGS. 22-24 show an alternative embodiment of a quick-connectionassembly 102. The illustrated assembly 102 includes the platform 198 andpedestal 192. The platform 198 includes tracks 200 adapted to receivetongues 206 attached on opposite sides of the vessel 100. One or morelift devices 208 are provided to raise the platform 198. In theillustrated embodiment, the lift devices 208 comprise bolts underneaththe platform 198. The bolts can be turned to cause the platform 198 torise to the connection position associated with the vessel 100. A guideapparatus (not shown) can be provided to maintain the vertical alignmentof the platform 198.

Vent Valve

As mentioned above, precursor source vessels are typically supplied witha head pressure of inert gas (e.g., helium) in the vessel. Duringventing of this head pressure down to typical process pressures, solidprecursor particles become aerosolized and entrained in the inert gasoutflow. This can contaminate the gas delivery system because such gasis typically vented out through the vessel's outlet isolation valve, thereactant gas delivery system, and ultimately the reactor'sexhaust/scrubber. Later, during substrate processing, the contaminatedportions of the gas panel that are common to the precursor delivery pathand the vent path can cause processing defects during ALD on thesubstrate.

In a preferred embodiment, this problem is substantially overcome byproviding an additional vent valve on the precursor source vessel and adedicated vent line in the gas delivery system for releasing the headpressure of gas inside the vessel, prior to processing. FIGS. 25-28illustrate an embodiment of this aspect of the invention. FIG. 25 is aschematic illustration of the gas delivery system 160 of FIG. 19, with avessel vent value 210 added to the precursor source vessel 100, and adedicated vent line 211 connected to the vent valve 210. The illustratedvent line 211 extends directly to the exhaust/scrubber. The vented gascan be released substantially without contaminating the gas deliverysystem that forms the path for precursor delivery to the reactionchamber 162, such as the components 110, 176, 166, 178 or the gas linestherebetween.

A surface mount flow restrictor can be added to the vessel vent valve210 to reduce the vent flow velocity, thus reducing turbulence thatmight otherwise stir up the precursor source (e.g., a powder). Suitablesurface mount flow restrictors are sold by Mott Corporation ofFarmington, Conn., also known as GSMR restrictors.

FIG. 26 shows an example of a precursor source vessel 100 that includesa vent valve 210. In this embodiment, the vent valve 210 is positionedintermediate the inlet isolation valve 108 and the outlet isolationvalve 110. However, skilled artisans will appreciate that otherarrangements are possible. Preferably, the vent valve 210 includes avalve porting block 212, which can be substantially similar to the valveporting blocks 118 and 120. FIG. 27 shows the vessel 100 of FIG. 26connected to the gas interface assembly of FIGS. 22-24, as describedabove.

FIG. 28 is a sectional view of an embodiment of the vessel 100 of FIG.26. As noted above, the vessel 100 includes a container body 104, aserpentine insert 112, a spring 114, a vessel lid 106. The vessel lid106 includes the surface-mounted isolation valves 108 and 110, as wellas the preferably surface-mounted isolation valve 210. Preferably, thevalves 108, 210, and 110 include valve porting blocks 118, 212, and 120,respectively. FIG. 28 also shows internal gas passages 214 of the valveporting blocks. As noted above, the valve porting block 120 includes agas outlet 128 that supplies the precursor vapor and carrier gas to thegas interface assembly 180.

A filter is preferably associated with each of the valves 108, 210, and110. In the illustrated embodiment, the vessel lid 106 includes a filter130 (e.g., as shown in FIG. 17 and described above) associated with eachvalve. It will be appreciated that a variety of different types offilters can be used. The filters prevent precursor particles fromexciting the vessel 100.

Although the invention has been disclosed in the context of certainembodiments and examples, it will be understood by those skilled in theart that the invention extends beyond the specifically disclosedembodiments to other alternative embodiments and/or uses and obviousmodifications and equivalents thereof. Accordingly, the invention is notintended to be limited by the specific disclosures of preferredembodiments herein.

What is claimed is:
 1. A chemical reactant source vessel in combinationwith a gas delivery system for a vapor phase reactor for vaporprocessing of substrates, comprising: a vessel body defining an internalchamber adapted to contain a solid or liquid chemical reactant, whereinthe vessel body includes an inlet and an outlet; an inlet passage withinthe vessel body, the inlet passage extending from outside the vesselbody to the vessel chamber; an inlet valve attached directly to asubstantially flat surface of the vessel body and configured to regulateflow through the inlet passage; an outlet passage within the vesselbody, the outlet passage extending from the vessel chamber to outsidethe vessel body; an outlet valve attached directly to the substantiallyflat surface of the vessel body and configured to regulate flow throughthe outlet passage; a vapor phase reaction chamber for processingsubstrates; a plurality of gas panel valves collectively operative toconvey a carrier gas through the vessel and into the reaction chamber,at least one of the gas panel valves being fluidly interposed betweenthe outlet valve and the reaction chamber; and a heater plate interposedbetween the gas panel valves and the flat surface of the vessel body,the heater plate configured to heat up the gas panel valves and thevessel; wherein all of the gas panel valves are positioned within about10.0 cm from the flat surface of the vessel body.
 2. The vessel and gasdelivery system combination of claim 1, wherein the inlet and outletvalves are each connected to the surface of the vessel body without anytubing between the valve and the surface of the vessel body.
 3. Thevessel and gas delivery system combination of claim 1, wherein the inletand outlet valves are each at least partly integrally formed with thevessel body.
 4. The vessel and gas delivery system combination of claim1, wherein each of the inlet and outlet valves comprises: a valveporting block mounted to or integrally formed with the vessel body, theporting block defining a valve seat and including internal gas flowconduits defining the passage, the gas flow conduits being in fluidcommunication with the valve seat; and a movable flow restrictor adaptedto block gas flow through the valve seat.
 5. The vessel and gas deliverysystem combination of claim 1, wherein the vessel body comprises: acontainer body; and a vessel lid adapted to engage the body to definethe chamber therebetween, the inlet and outlet passages being within thelid, the inlet and outlet valves being attached directly to the lid. 6.The vessel and gas delivery system combination of claim 1, wherein thechamber includes a tortuous path configured to contain the chemicalreactant, the tortuous path extending from the inlet to the outlet. 7.The vessel and gas delivery system combination of claim 6, furthercomprising a serpentine insert within the chamber, the serpentine insertdefining the tortuous path.
 8. The vessel and gas delivery systemcombination of claim 6, further comprising a stack of trays within thechamber, the trays collectively defining a spiral gas flow path thatcomprises at least a portion of the tortuous path.
 9. The vessel and gasdelivery system combination of claim 6, wherein the tortuous path ismachined into the container body or a lid of the vessel.
 10. The vesseland gas delivery system combination of claim 1, wherein the gas panelvalves are each positioned along a plane that is generally parallel tothe flat surface of the vessel body, the plane being no more than about10.0 cm from the flat surface of the vessel body.
 11. The vessel and gasdelivery system combination of claim 10, wherein the heater plate isinterposed between the plane and the flat surface of the vessel body.12. The vessel and gas delivery system combination of claim 10, whereinthe plane is no more than about 7.5 cm from the flat surface of thevessel body.
 13. The vessel and gas delivery system combination of claim12, wherein the plane is no more than about 5.3 cm from the flat surfaceof the vessel body.
 14. The vessel and gas delivery system combinationof claim 1, wherein the gas panel valves are part of a gas panelcomprising: a fluid conduit adapted to receive a carrier gas and conveythe carrier gas to a first gas conduit connection point; a first gaspanel valve fluidly interposed between the first gas conduit connectionpoint and the inlet valve attached to the vessel; a second gas panelvalve fluidly interposed between the first gas conduit connection pointand a second gas conduit connection point; a third gas panel valvefluidly interposed between the second gas conduit connection point andthe outlet valve attached to the vessel; and a fourth gas panel valvefluidly interposed between the second gas conduit connection point andthe reaction chamber.
 15. The vessel and gas delivery system combinationof claim 1, further comprising: a vapor exhaust component downstream ofthe reaction chamber; a vent passage extending through the vessel bodyfrom the vessel chamber to outside the vessel; a vent valve attacheddirectly to the vessel body and configured to regulate flow through thevent passage; and one or more conduits for delivering gas flow from thevent valve to the exhaust component without flowing through the reactionchamber.
 16. The vessel and gas delivery system combination of claim 1,further comprising a filter in a wall of the vessel body, the filteradapted to prevent particulate matter from flowing through the outletpassage.
 17. The vessel and gas delivery system combination of claim 16,wherein an inner surface of the wall includes a recess that receives thefilter, the outlet passage having one end terminating in the recess andanother end in fluid communication with the outlet valve, the filtercomprising: a flange having an inner annular wall defining an openingwithin the flange, the flange being positioned within the recess; and afilter material substantially filling the opening of the flange; whereingas within the internal chamber of the vessel body cannot flow throughthe outlet passage without flowing through the filter material and theopening within the flange.
 18. The vessel and gas delivery systemcombination of claim 1, further comprising: a first filter in a wall ofthe vessel body, the first filter adapted to prevent particulate matterfrom flowing through the inlet passage; and a second filter in the wallof the vessel body, the second filter adapted to prevent particulatematter from flowing through the outlet passage.
 19. The vessel and gasdelivery system combination of claim 18, wherein: an inner surface ofthe vessel body wall includes a first recess that receives the firstfilter, and a second recess that receives the second filter; the inletpassage has one end terminating in the first recess and another end influid communication with the inlet valve; the outlet passage has one endterminating in the second recess and another end in fluid communicationwith the outlet valve; the first filter comprises: a first flange havingan inner annular wall defining an opening within the first flange, thefirst flange being positioned within the first recess; and a firstfilter material substantially filling the opening of the first flange;the second filter comprises: a second flange having an inner annularwall defining an opening within the second flange, the second flangebeing positioned within the second recess; and a second filter materialsubstantially filling the opening of the second flange; the first filteris engaged with the first recess and configured so that gas cannot flowthrough the inlet passage without flowing through the first filtermaterial and the opening within the first flange; and the second filteris engaged with the second recess and configured so that gas cannot flowthrough the outlet passage without flowing through the second filtermaterial and the opening within the second flange.